#!/usr/bin/env python3
"""
Script to synchronize (local>remote and viceversa) test data files from/to GCS.

//test/data files are not checked in the codebase because they are large binary
file and change frequently. Instead we check-in only xxx.sha256 files, which
contain the SHA-256 of the actual binary file, and sync them from a GCS bucket.

File in the GCS bucket are content-indexed as gs://bucket/file_name-a1b2c3f4 .

Usage:
./test_data status     # Prints the status of new & modified files.
./test_data download   # To sync remote>local (used by install-build-deps).
./test_data upload     # To upload newly created and modified files.
"""

import argparse
import logging
import os
import sys
import hashlib
import subprocess

from multiprocessing.pool import ThreadPool
from collections import namedtuple, defaultdict

ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
BUCKET = 'gs://perfetto/test_data'
SUFFIX = '.sha256'

FS_MATCH = 'matches'
FS_NEW_FILE = 'needs upload'
FS_MODIFIED = 'modified'
FS_MISSING = 'needs download'

FileStat = namedtuple('FileStat',
                      ['path', 'status', 'actual_digest', 'expected_digest'])
args = None


def relpath(path):
  return os.path.relpath(path, ROOT_DIR)


def download(url, out_file):
  subprocess.check_call(['curl', '-L', '-s', '-o', out_file, url])


def list_files(path, scan_new_files=False):
  """ List files recursively in path.

  If scan_new_files=False, returns only files with a maching xxx.sha256 tracker.
  If scan_new_files=True returns all files including untracked ones.
  """
  seen = set()
  for root, _, files in os.walk(path):
    for fname in files:
      if fname.endswith('.swp'):
        continue  # Temporary files left around if CTRL-C-ing while downloading.
      fpath = os.path.join(root, fname)
      if not os.path.isfile(fpath) or fname.startswith('.'):
        continue
      if fpath.endswith(SUFFIX):
        fpath = fpath[:-len(SUFFIX)]
      elif not scan_new_files:
        continue
      if fpath not in seen:
        seen.add(fpath)
        yield fpath


def hash_file(fpath):
  hasher = hashlib.sha256()
  with open(fpath, 'rb') as f:
    for chunk in iter(lambda: f.read(32768), b''):
      hasher.update(chunk)
  return hasher.hexdigest()


def map_concurrently(fn, files):
  done = 0
  for fs in ThreadPool(args.jobs).imap_unordered(fn, files):
    assert (isinstance(fs, FileStat))
    done += 1
    if not args.quiet:
      print(
          '[%d/%d] %-60s' % (done, len(files), relpath(fs.path)[-60:]),
          end='\r')
  if not args.quiet:
    print('')


def get_file_status(fpath):
  sha_file = fpath + SUFFIX
  sha_exists = os.path.exists(sha_file)
  file_exists = os.path.exists(fpath)
  actual_digest = None
  expected_digest = None
  if sha_exists:
    with open(sha_file, 'r') as f:
      expected_digest = f.readline().strip()
  if file_exists:
    actual_digest = hash_file(fpath)
  if sha_exists and not file_exists:
    status = FS_MISSING
  elif not sha_exists and file_exists:
    status = FS_NEW_FILE
  elif not sha_exists and not file_exists:
    raise Exception(fpath)
  elif expected_digest == actual_digest:
    status = FS_MATCH
  else:
    status = FS_MODIFIED
  return FileStat(fpath, status, actual_digest, expected_digest)


def cmd_upload(dir):
  all_files = list_files(dir, scan_new_files=True)
  files_to_upload = []
  for fs in ThreadPool(args.jobs).imap_unordered(get_file_status, all_files):
    if fs.status in (FS_NEW_FILE, FS_MODIFIED):
      files_to_upload.append(fs)
  if len(files_to_upload) == 0:
    if not args.quiet:
      print('No modified or new files require uploading')
    return 0
  if args.dry_run:
    return 0
  if not args.quiet:
    print('About to upload %d files:' % len(files_to_upload))
    print('\n'.join(relpath(f.path) for f in files_to_upload))
    print('')
    input('Press a key to continue or CTRL-C to abort')

  def upload_one_file(fs):
    assert (fs.actual_digest is not None)
    dst_name = '%s/%s-%s' % (args.bucket, os.path.basename(
        fs.path), fs.actual_digest)
    cmd = ['gsutil', '-q', 'cp', '-n', '-a', 'public-read', fs.path, dst_name]
    logging.debug(' '.join(cmd))
    subprocess.check_call(cmd)
    with open(fs.path + SUFFIX + '.swp', 'w') as f:
      f.write(fs.actual_digest)
    os.replace(fs.path + SUFFIX + '.swp', fs.path + SUFFIX)
    return fs

  map_concurrently(upload_one_file, files_to_upload)
  return 0


def cmd_download(dir, overwrite_locally_modified=False):
  files_to_download = []
  modified = []
  all_files = list_files(dir, scan_new_files=False)
  for fs in ThreadPool(args.jobs).imap_unordered(get_file_status, all_files):
    if fs.status == FS_MISSING:
      files_to_download.append(fs)
    elif fs.status == FS_MODIFIED:
      modified.append(fs)

  if len(modified) > 0 and not overwrite_locally_modified:
    print('WARNING: The following files diverged locally and will NOT be ' +
          'overwritten if you continue')
    print('\n'.join(relpath(f.path) for f in modified))
    print('')
    print('Re run `download --overwrite` to overwrite locally modified files')
    print('or `upload` to sync them on the GCS bucket')
    print('')
    input('Press a key to continue or CTRL-C to abort')
  elif overwrite_locally_modified:
    files_to_download += modified

  if len(files_to_download) == 0:
    if not args.quiet:
      print('Nothing to do, all files are synced')
    return 0

  if not args.quiet:
    print('Downloading %d files in //%s' %
          (len(files_to_download), relpath(args.dir)))
  if args.dry_run:
    print('\n'.join(files_to_download))
    return

  def download_one_file(fs):
    assert (fs.expected_digest is not None)
    uri = '%s/%s-%s' % (args.bucket, os.path.basename(
        fs.path), fs.expected_digest)
    uri = uri.replace('gs://', 'https://storage.googleapis.com/')
    logging.debug(uri)
    tmp_path = fs.path + '.swp'
    download(uri, tmp_path)
    digest = hash_file(tmp_path)
    if digest != fs.expected_digest:
      raise Exception('Mismatching digest for %s. expected=%s, actual=%s' %
                      (uri, fs.expected_digest, digest))
    os.replace(tmp_path, fs.path)
    return fs

  map_concurrently(download_one_file, files_to_download)
  return 0


def cmd_status(dir):
  files = list_files(dir, scan_new_files=True)
  file_by_status = defaultdict(list)
  num_files = 0
  num_out_of_sync = 0
  for fs in ThreadPool(args.jobs).imap_unordered(get_file_status, files):
    file_by_status[fs.status].append(relpath(fs.path))
    num_files += 1
  for status, rpaths in sorted(file_by_status.items()):
    if status != FS_MATCH:
      for rpath in rpaths:
        num_out_of_sync += 1
        if not args.quiet:
          print('%-15s: %s' % (status, rpath))
  if num_out_of_sync == 0:
    if not args.quiet:
      print('Scanned %d files in //%s, everything in sync.' %
            (num_files, relpath(dir)))
    return 0
  return 1


def main():
  parser = argparse.ArgumentParser()
  parser.add_argument('--dir', default=os.path.join(ROOT_DIR, 'test/data'))
  parser.add_argument('--overwrite', action='store_true')
  parser.add_argument('--bucket', default=BUCKET)
  parser.add_argument('--jobs', '-j', default=10, type=int)
  parser.add_argument('--dry-run', '-n', action='store_true')
  parser.add_argument('--quiet', '-q', action='store_true')
  parser.add_argument('--verbose', '-v', action='store_true')
  parser.add_argument('cmd', choices=['status', 'download', 'upload'])
  global args
  args = parser.parse_args()
  logging.basicConfig(
      format='%(asctime)s %(levelname).1s %(message)s',
      level=logging.DEBUG if args.verbose else logging.INFO,
      datefmt=r'%H:%M:%S')
  if args.cmd == 'status':
    return cmd_status(args.dir)
  if args.cmd == 'download':
    return cmd_download(args.dir, overwrite_locally_modified=args.overwrite)
  if args.cmd == 'upload':
    return cmd_upload(args.dir)
  print('Unknown command: %s' % args.cmd)


if __name__ == '__main__':
  sys.exit(main())
